Answer: The equations that represent circles that have a diameter of 12 units and a center that lies on the y-axis are:
(x – 6)² + y² = 36
x2 + (y + 6)² = 36
Because a diameter is the distance between two points on a circle that is farthest from each other, the radius of the process must be half of the diameter. So the radius of the ring is 6 units.
The center of the circle must be on the y-axis, it means that the x coordinate of the center is 0, so the equation of the circle will be (x - h)² + (y - k)² = r² where h = 0, k = center on the y-axis, and r = 6.
The first equation, x2 + (y – 3)2 = 36, doesn't represent a circle with a center on the y-axis, because the center of the circle is represented by (0, 3) which is not on the y-axis.
The second equation x2 + (y – 5)2 = 6 doesn't represent a circle with a diameter of 12 units, because the value of the equation is 6 which is not equal to the square of the radius.
The third equation, (x – 4)² + y² = 36, doesn't represent a circle with a center on the y-axis, because the center of the circle is represented by (4, 0) which is not on the y-axis.
The forth equation, (x + 6)² + y² = 144, doesn't represent a circle with a diameter of 12 units, because the value of the equation is 144 which is not equal to the square of the radius.
The fifth equation, x2 + (y + 8)² = 36, doesn't represent a circle with a diameter of 12 units, because the value of the equation is 36 which is not equal to the square of the radius.
Explanation: